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21 University of Texas at Austin Condition Codes (Explicit Setting: Test) Explicit Setting by Test instruction testl / testq Src2, Src1 testl b,a like computing a&b without setting destination Sets condition codes based on value of Src1 & Src2 Useful to have one of the operands be a mask ZF set when a&b == 0 SF set when a&b < 0